On the corner of my street, neighbors are saying goodbye to what was easily the most beautiful maple tree most of us have ever seen. At first they thought drought was responsible for the smattering of dead branches at the top of the tree’s canopy. But when watering more diligently didn’t solve the problem, they called in an arborist, who told them it was too late to help the dying tree. The problem? It was planted incorrectly. Now, two decades later, it was being strangled by its own roots because it had been buried too deeply.
The people who planted that maple likely thought they were doing the right thing at the time. It was once considered good advice to plant trees deeply. The thinking was that young trees would be less susceptible to being blown over by high winds, and tree roots would be better protected from the elements by being buried deep underground.
As my neighbors found out, this was bad advice. More recent studies show that a different approach ensures healthier trees. Here are the steps now recommended for planting (and caring for) trees. And this is the perfect time of year to try them out!
the proper time
Climate plays a big role in choosing the right time to plant trees, and because of that there’s a fair amount of debate over which trees do best when planted in spring or fall. In northern states, for example, most trees do best when they’re planted in the fall. Birch, pines, and redbuds are an exception. Those trees tend to die when planted in the fall, so they’re best planted in the spring.
If you live in a warm climate, any time except summer is typically a good time to plant container-grown and balled-and-burlapped trees. If you live in a region with cold winters where the ground freezes, spring and fall are considered the best times to plant, but summer is okay, too. Depending on where you live, spring and fall are the best times to plant bare-root trees, which have no soil around their roots.
Always match your tree with the conditions your site offers. Soil type, drainage, and sun exposure should all be considered. Above all, though, choose a location where the tree can reach its maximum height and width listed on the plant tag. Too often, mature trees have to be cut down or pruned beyond recognition because they interfere with overhead utility wires or block windows and driveways.
Remember, too, that location can also influence temperature and moisture levels. Westerly winds, for example, can dry out trees quickly in unprotected areas. And trees planted on the south side of a building will be much warmer and drier in winter than those planted on the north side. This is fine for some trees, but evergreens are easily damaged when warming causes too much water loss in colder months.
watch the flare
Planting trees deeply is one of the biggest reasons why trees die. Look around: If you see a tree trunk that looks like a telephone pole shooting straight into the ground, it’s planted too deeply. What you want to see just above the soil is the tree’s natural root flare, a slight bulge at the base of the trunk where it transitions into the root ball.
Planting trees so that the root flare is visible rather than buried ensures that the roots will be close enough to the soil surface to get the air, water, and nutrients they need. Roots have a job to do, and they have to get to the soil surface to do it. If you plant a tree too deeply, it may take 10 to 20 years, but those roots will grow up in an attempt to get closer to the surface. As they do, they’ll circle the base of the tree and girdle it, essentially strangling it.
To plant a tree correctly, ignore advice to plant trees at the same depth they’re planted in the nursery container. It’s very common to find containerized trees that are planted too deeply. Gently remove your tree from its container and use your hands or a trowel to scrape away the top layer of soil until you find the root flare. Don’t be surprised if you have to dig down several inches. Once you’ve exposed the flare, plant your tree, keeping the flare just above the soil surface.
stake only if needed
You may have heard the old advice that all young trees should be staked. New research, however, has shown that it’s better to forego the stability offered by staking and allow young trees to move freely in the wind. Doing this helps trees develop strong, tapered trunks, which will give them their own lifelong stability. Too much support for too long can make trees more likely to break or blow down.
There are exceptions, however. Trees planted in areas where they’ll be exposed to high winds do benefit from staking during their first year in the ground. So do trees with naturally flexible stems, such as some types of oaks, because they might not grow straight if they aren’t staked.
Stake trees for no more than one year, and be sure that the stakes give the tree enough room to move freely. Use two metal or wooden stakes, and place them equidistant from the trunk. Bury stakes about 2 feet deep to provide adequate support. Use soft, flexible materials as ties to avoid harming the bark. Place the ties about a third of the way up the trunk.
Check on your staking system often to be sure the tree doesn’t become choked or damaged because stakes have fallen or ties have become misaligned.
help it survive
Young trees often don’t make it through their first year or two of life. One of the biggest reasons is not enough water. While established trees need about an inch each week to thrive, young trees often need more than that for the first couple of years, especially during very hot weather. Their root systems are small and unable to sustain them through periods of heat and dryness.
Mulch helps newly planted trees retain moisture and moderate soil temperature. Two or three inches works best. Spread the mulch out in a circle around the base, keeping the mulch flat rather than mounded and about 3 inches away from the trunk. If critters are a problem, use rabbit fencing or another type of fencing to circle the trunk and keep them out.
three planting options
Just like annuals and perennials, trees can be purchased in several different forms.
These trees look a bit like fragile broomsticks when you buy them. They’re dug from the nursery in spring or fall, and all of the soil is removed from the roots. Bare-root trees are lightweight and easy to plant, and they’re also much less expensive than other options. But be sure to keep the roots moist until planting time.
Containerized trees are available in a variety of sizes, but it’s best to buy the smallest one possible because younger trees with well-established root systems typically suffer less shock and establish themselves faster than trees in larger pots. These trees can become root-bound, however, so be sure to slide them out of their containers and inspect the roots before you buy them.
Avoid buying extremely root-bound trees because they’re already experiencing stress.
Dug from the ground in a manner that keeps a good-sized root ball intact, these trees are larger at planting time. They require a wire basket, burlap, and twine or metal wiring to hold all the soil in place. It takes some maneuvering, and usually some equipment, to plant them. They’re more expensive than other options and are fairly susceptible to transplant shock. Diligent watering is a must.
Illustrations: Elara Tanguy